Laminated flexwood spring for chair seats



April 13 1943. A, J. SCHAFFNER LAMINATED FLEXWOOD :SPRING FOR CHAIR SEATS 2 Sheets-Sheet 1 Filed May 16, 1942 P 1943- A. J. SCHAFFNER 2,316,628 Lmxm'mnimaxwobn SPRING FOR CHAIR SEATS Filed May 16, 1942 2 Sheets-Sheet 2 Patented Apr. 13, 1943 LAMINATED FLEXWOOD SPRING FOR CHAIR SEATS Alvin J. Schaffner, Aurora, Ill., assignor to Kroehler Mfg. 00., Naperville, 111., a corporation of Illinois ApplicationMaylfi, 1942, Serial No. 443,249

4 Claims.

This invention relates to a laminated flexwood spring for chair-seats and consists of the matters hereinafter describe and more particularly pointed out in the appendedclaims.

The object of the invention is to provide a novel and improved leaf spring construction made of laminated wood or flexwood which may be readily applied to a chair seat and which will give to said seat the required resilient flexibility heretofore provided by the use .ofsteel coiled .or other steel springs.

Another object of the invention is to provide a construction of chair seat, including flexwood springs, which is capable of ready and easy assembly and which may be produced .at a small cost.

Another object of the invention is to provide a flexwood spring unit which is so assembled and so applied to the frame by which it iscarried that it has no .fixed anchorage and will give free movement.

The advantages of the invention will appear more fully as I proceed with my specification.

In the drawings:

Figure 1 is a perspectiveview of a chairof any familiar construction, with the .seat upholstered in the usual manner and containingtheimproved flexwood spring of the invention.

Figure 2 is a vertical section, in a plane indicated by the line 2-2 of Figurel, with the outline of the upholstery of the seat indicated by dotted lines.

Figure 3 is a perspective view of the spring unit.

Figure 4 is a perspective view of a pair of the upper and lower leaves of the flexwoodspring unit shown applied to the front and back rails .of the seat of th chair.

Figure 5 is a top plan view of the spring unit shown in Figure 3 in perspective.

Figure 6 in view representing a section through Figure 5 in a plane indicated by the line 6-6 in Figure 5.

Figure 7 is a view representing a section through Figure 6 in a plane indicated by the line 1-1 of Figure 6.

Figure 8 is a front elevation of the spring unit shown in Figure 5.

Figure 9 is a view representing a section through Figure 6 in a plane indicated by the line 99 of Figure 6. s

Figure 10 is a rear elevation of the spring unit as shown in Figure 5.

Referring now to that embodiment of the invention illustrated in the drawings: ll indicates the seat of a chair mad of wood in the usual manner. I2 indicates the front rail, and i3 indicates the back rail of the chair seat. I4 indicates the spring unit. Said springunit comprises an upper member l5 and a lower member 15. The upperspring member l5 consists of a plurality .of laterally spaced parallel flexwood spring leaves l5 attached at their rear ends to a depending rocker bar I! which extends transversely of said leaves and are attached at their front ends to a flat plywoodstrip l8 extending transversely across their top faces. The lower spring member It consists of a plurality of laterally spaced parallel flexwood spring leaves I 6 attached at their front ends. to a depending rocker 'bar I 9 which extends transversely of and depends below said leaves. Each spring .member contains .a like number of leaves, :and the leaves .of the upper member are disposed upon and engage theleaves of the lower member.

'The leaves l5 .of the upper spring member are formed with a slight downward curvature. The vspringe leaves l6? of the lower spring member are straight at the ends, but are formed with a reverse curve towards the main body of the .leaf which is straight and is incontact with an associated leaf Iii of the upper spring .member as clearlyshown. in- Figures 2, .3 and 4. The leaves 1.6! of the lower spring member are extended somewhat. beyond the, rocker bar i! of the upper spring member as shown in Figures 2 and 3.

The front rail l2 of thechair seat is provided at .its upper edge with a rounded groove 20 in which .seats the rocker bar i9 which has a correspondingly transversely rounded bottom edge 13*. 1

The rearrail ,l3 of the chair seat is provided with a plurality of slots 2| laterally spaced to correspond with the ,spacing'of theleaves [6 of the bottom spring member, the rear ends 16 of which leaves extend through said slots when the spring assembly is mounted on the chair seat frame. As shown, the back rail of the chair seat is formed in two pieces l3, Iii disposed edge to edge, one upon the other, and one or the other, the upper piece as shown, is notched to provide, together with the proximate edge of the other piece, the slots 2|.

The rocker bar I1 has a rounded bottom ll and rests in one or more notched cradle blocks 22 disposed between the slots 2| and fixed to the inside face of the back seat rail l3. Thus the spring unit is capable of a free rocking movement upon the front seat rail I2 and also on the back rail l3, such movement being permitted by the fact that the ends W of the leaves of the bottom spring member l6 extend through the slots 2|, and that the front ends of the spring leaves l are free as shown in Figures 2 and 6.

A paper cord 23 is attached to the fiexwood strip I8 at the front end of the upper spring member, as shown in Figure 2. This provides a seat roll to support and round out the cover sheet of the'upholstery at the front edge of the seat.

From the foregoing description it will be obvious to those familiar with the art that the novel flexwood spring unit will provide the required elasticity and great freedom of movement without any fixed anchorage.

Straight grain woods and semi-flexible waterproof glue are used in the manufacture of the laminated spring leaves. They are given the required form or shape and are so treated in a familiar manner, that when finished they will maintain their shape and form equally as well as similar springs manufactured from steel.

While in describing my invention I have shown it as applied to a chair seat frame, it is to be understood that the invention is not limited thereto since it may be applied to other frames where its construction and operation may be required.

I claim as my invention:

1. A laminated fiexwood spring construction comprised of upper and lower members, each having a like number of laterally spaced flex wood spring leaves, the leaves of the upper spring member {being bent downwardly intermediate their ends, and the leaves of the bottom spring member being bent upwardly intermediate their ends into engagement with associated spring leaves of the upper spring member, a depend ing rocker bar fixed to the rear end of the upper spring member, a second depending rocker bar fixed to the front end of the bottom spring member, and a strip attached to and extending transversely of the ends of the leaves of the upper spring member, the leaves of said bottom spring member extending beyond the rocker bar of the upper member.

2. A laminated fiexwood spring construction comprising an open frame having front and back rails, a spring unit comprised of upper and. lowermembers each having a like number of laterally spaced fiexwood spring leaves, the leaves of the upper springmember being bent downwardly intermediate their ends, and the leaves of the bottom spring member being bent up wardly intermediate their ends into engagement with associated spring leaves of the upper spring member, a depending rocker bar fixed to the rear end of the upper spring member, a second depending rocker bar fixed to the front end of the bottom spring member, a strip attached to and extending transversely of the ends of the leaves of the upper spring member, the leaves of said bottom spring member extending beyond the rocker bar of the upper member, and means on said frame providing seats for said rocker bars, and said back rail being provided with laterally spaced slots through which the rear ends of the leaves of said bottom spring member project,

3. A laminated flexwood spring chair seat construction comprising an open chair seat frame having front and back rails, a spring unit comprised of upper and lower members each having a like number of laterally spaced flexwood spring leaves, the leaves of the upper spring member being bent downwardly intermediate their ends, and the leaves of the bottom spring member being bent upwardly intermediate their ends into engagement with associated spring leaves of the upper spring member, a depending rocker bar fixed to the rear end of the upper spring member, a second depending rocker bar fixed to the front end of the bottom spring member, a strip attached to and extending transversely of the ends of the leaves of the upper spring member, the leaves of said bottom spring member extending beyond the rocker bar of the upper member, and said back rail being provided with laterally spaced slots through which the rear ends of the leaves of said bottom spring member project.

4. Alaminated fiexwood spring chair seat construction comprising an open chair seat frame having front and back rails, a spring unit comprised of upper and lower members each having a like number of laterally spaced flexwood spring leaves, the leaves of the upper spring member being bent downwardly intermediate their ends, and. the leavesof the bottom spring member being bent upwardly intermediate their ends into engagement with associated spring leaves of the upper spring member, a depending rocker bar fixed tothe rear end of the upper spring member, a second depending rocker bar fixed to the front end of the bottom spring member, a strip attached to and extending transversely of the ends .of the leaves of the upper spring member, the

leaves of said bottom spring member extending beyond the rocker bar of the upper member,

said back rail being provided with laterally spaced slots through which the rear ends of the leaves of said bottom spring member project, the

.topedg'e of said front rail being grooved to seat the rocker bar of said bottom frame, and a cradle fixed to said back rail providing a seat for the rocker bar of said top spring member.

ALVIN J. SCHAFFNER. 

